JP2000104614A - Road surface grade estimating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately estimate the road surface grade in any condition by considering the driving system loss torque and the turning resistance torque, besides the flat road traveling resistance torque and the acceleration resistance torque. SOLUTION: A driving system loss torque Tlos is computed on the basis at least one of oil pressure Pl, oil temperature Tmp, the number of revolution of input shaft Nin, change gear ratio Ip of a transmission. An effective vehicle driving torque Toy is computed by subtracting the driving system loss torque Tlos from an ideal vehicle driving torque Tor. The grade resistance torque Trg is computed by subtracting the flat road traveling resistance torque Trl and the acceleration resistance torque Tra from the effective vehicle driving torque Toy, and the road surface grade during the traveling is computed on the basis of the grade resistance torque Trg. The grade resistance torque Trg can be also computed by computing the turning resistance torque Tcorn on the basis of the steering angle of the vehicle and subtracting the turning resistance torque Tcorn from the effective vehicle driving torque Toy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road gradient estimating apparatus for estimating a road gradient during traveling.

[0002]

2. Description of the Related Art There is known a vehicle which is provided with a device for estimating a road surface gradient during traveling in order to improve running performance on an uphill road or the like, and which changes vehicle characteristics according to the estimated road surface gradient.

As a conventional road surface gradient estimating device, there is one described in Japanese Patent Application Laid-Open No. Hei 3-24362.
This is not sufficient for estimating an accurate road gradient only by judging the magnitude of the gradient from the vehicle speed, the throttle opening, or the speed of change thereof.

Therefore, a road surface gradient estimating device described in Japanese Patent Application Laid-Open No. Hei 9-242862 calculates an input torque to an automatic transmission and calculates a vehicle drive torque by multiplying the input torque by a transmission ratio of the transmission. The gradient resistance torque is calculated by subtracting the flat road running resistance torque and the acceleration resistance torque from the vehicle driving torque, and the road surface gradient is estimated from the gradient resistance torque to improve the accuracy.

[0005]

Problems to be Solved By the way, the flat road running resistance torque and the acceleration resistance torque are subtracted from the vehicle driving torque to obtain the slope resistance torque, and the road surface slope is estimated based on the slope resistance torque. In this case, in order to accurately perform the gradient estimation, it is necessary to accurately calculate the vehicle driving torque, the flat road running resistance torque, and the acceleration resistance torque.

However, in the above prior art,
Since the drive system loss torque was not considered, the vehicle drive torque was not accurately calculated, and the road surface gradient could not be estimated with high accuracy. In order to accurately calculate the vehicle drive torque, it is necessary to consider a drive system loss torque that changes depending on the hydraulic pressure, the oil temperature, the input shaft rotation speed, and the gear ratio. Further, in the above-described related art, it is difficult to estimate a road gradient at the time of turning because the turning resistance torque lost at the time of turning is not considered.

SUMMARY OF THE INVENTION The present invention has been made in view of such technical problems, and considers a drive system loss torque and a turning resistance torque, which were not taken into consideration in the prior art, so that the road surface gradient in any situation can be accurately determined. It is an object of the present invention to provide a road surface gradient estimating device capable of well estimating.

[0008]

According to a first aspect of the present invention, there is provided a road surface gradient estimating apparatus for calculating an ideal vehicle driving torque by multiplying a driving system input torque by a driving system gear ratio, and a transmission hydraulic pressure. Means for calculating a drive system loss torque based on at least one of an oil temperature, an input shaft rotation speed, and a gear ratio; and means for calculating an effective vehicle drive torque by subtracting a drive system loss torque from the ideal vehicle drive torque. Means for calculating flat road running resistance torque based on vehicle speed, means for calculating acceleration resistance torque based on vehicle acceleration, and slope resistance torque by subtracting flat road running resistance torque and acceleration resistance torque from the effective vehicle driving torque. And means for calculating a road surface gradient during traveling from the gradient resistance torque.

According to a second aspect, in the first aspect, a means for calculating an output torque of the engine, a means for calculating an inertia torque of the engine, a means for calculating a torque ratio of the torque converter, and a transmission of the transmission Means for calculating a ratio, the means for calculating the ideal vehicle drive torque,
A drive system input torque is calculated based on an engine output torque, an engine inertia torque, and a torque ratio, and an ideal vehicle drive torque is calculated by multiplying the input torque by a gear ratio.

According to a third aspect of the present invention, in the second aspect, the means for calculating the inertia torque of the engine calculates the engine inertia torque by multiplying a value obtained by differentiating the engine speed over time by the engine inertia. Is what you do.

In a fourth aspect based on the first to third aspects, the means for calculating the acceleration resistance torque obtains the acceleration of the vehicle by differentiating the vehicle speed with respect to time, and multiplies the acceleration by the weight of the vehicle and the radius of the driving wheel. Thus, the acceleration resistance torque is calculated.

According to a fifth aspect of the present invention, in the first to fourth aspects, there is provided means for detecting a steering angle of the vehicle, and means for calculating a turning resistance torque based on the detected steering angle. The calculating means calculates the gradient resistance torque by subtracting the flat road running resistance torque, the acceleration resistance torque and the turning resistance torque from the effective vehicle driving torque.

According to a sixth aspect, in the fifth aspect, the means for calculating the turning resistance torque does not calculate the turning resistance torque when the steering angle or the vehicle speed is equal to or less than a threshold value. .

According to a seventh aspect of the present invention, in the first to fourth aspects, means for detecting the position of the own vehicle, means for calculating the radius of curvature of the road at the own vehicle position based on the map information, and the calculated radius of curvature Means for calculating a turning resistance torque based on the following formula, wherein the means for calculating the slope resistance torque calculates the slope resistance torque by subtracting the flat road running resistance torque, the acceleration resistance torque and the turning resistance torque from the effective vehicle driving torque. It is characterized by the following.

[0015]

According to the first aspect of the invention, a gradient resistance torque is calculated from an effective vehicle drive torque obtained by subtracting a drive system loss torque from an ideal vehicle drive torque, a flat road running resistance torque, and an acceleration resistance torque. The road surface gradient during traveling is estimated from the gradient resistance torque. As described above, since the road surface gradient is estimated in consideration of the drive system loss torque, the road surface gradient can be estimated with better accuracy, and the error of the gradient estimation due to the influence of the drive system loss torque that changes according to the driving situation is reduced. be able to.

At this time, the drive system loss torque is calculated according to at least one of the hydraulic pressure of the transmission, the oil temperature, the input shaft rotation speed, and the gear ratio. The gradient can be estimated. In addition, since the flat road running resistance torque is obtained by referring to a map showing the relationship between the vehicle speed and the flat road running resistance torque, it is not necessary to provide a torque sensor for calculating the running resistance torque, and the configuration of the device is reduced. It becomes simple and cost can be reduced.

According to the second invention, the ideal vehicle drive torque calculating section calculates the drive system input torque by multiplying the value obtained by subtracting the engine inertia torque from the engine output torque by the torque ratio of the torque converter, and further calculates the input torque. The ideal vehicle drive torque is calculated by multiplying the gear ratio by the final reduction ratio.
This eliminates the need for a torque sensor when calculating the ideal vehicle drive torque, thereby simplifying the device configuration and reducing costs.

According to the third aspect, the engine inertia torque calculation unit calculates the engine inertia torque by multiplying the value obtained by time-differentiating the engine speed by the engine inertia constant. By considering the engine inertia torque in this way, the accuracy of estimating the road surface gradient when the engine speed increases or decreases is improved.

According to the fourth aspect, the acceleration resistance torque calculation section calculates the acceleration by differentiating the vehicle speed with respect to time, and obtains the acceleration resistance torque by multiplying the acceleration by the vehicle weight and the radius of the driving wheel. This eliminates the need to provide an acceleration sensor to calculate the acceleration, thereby simplifying the configuration of the device and reducing the cost.

According to the fifth aspect, the turning resistance torque is calculated according to the vehicle speed and the steering angle, and the gradient resistance torque is calculated in consideration of the turning resistance torque. Thus, by taking into account the torque lost during turning, the accuracy of gradient estimation during turning can be increased. Further, since the turning resistance torque is obtained from the two factors of the vehicle speed and the steering angle, the turning resistance torque can be accurately calculated according to all turning conditions.

According to the sixth aspect, the turning resistance torque calculation section sets a threshold value for the vehicle speed or the steering angle. When the turning resistance torque is equal to or smaller than the threshold value or equal to or larger than the threshold value, the road surface gradient is calculated without considering the turning resistance torque. presume. In this way, by providing a threshold value for the vehicle speed or the steering angle, in a situation where the turning resistance torque does not affect the estimation of the road surface gradient, the calculation process of the turning resistance torque is omitted, and the load on the calculation can be reduced. .

According to the seventh aspect, the turning resistance torque is calculated from the radius of curvature of the road on which the vehicle is present and the vehicle speed, and the gradient resistance torque is calculated in consideration of the turning resistance torque. By calculating the road gradient based on the map information and the vehicle position information from the satellite in advance in this way, without being affected by changes in driving force characteristics due to changes in vehicle conditions such as tire puncture and aging, The road gradient can be detected accurately.

[0023]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a road surface gradient estimating apparatus 11 according to the present invention.
1 shows a schematic configuration of a CVT-equipped vehicle 101 provided with 0. The drive system of the vehicle 101 includes a torque converter 10
4 with a built-in CVT 4 and a propeller shaft 105
And final gear and differential gear 106
And a drive shaft 107 connecting the differential gear 106 and the drive wheel 108.
2 is transmitted to the drive wheels 108.

Here, the CVT 103 means a V-belt type continuously variable transmission, but may have a continuously variable transmission of another structure such as a toroidal type continuously variable transmission, or may have a planetary gear and a clutch member. May be a stepped automatic transmission. Although the vehicle 101 shown in FIG. 1 is driven by rear wheels, another driving method may be used.

The engine 102 is provided with a crank angle sensor 121 for detecting a rotation speed Ne of a crankshaft which is an output shaft of the engine 102. A throttle valve for adjusting the amount of air passing through the intake passage in accordance with the operation of the accelerator pedal is provided in the intake passage of the engine 102, and the valve opening TVO of the throttle valve is detected by the throttle opening sensor 122. .

The CVT 103 includes a hydraulic control circuit including a control valve and the like and a step motor, and performs a stepless speed change according to the rotational position of the step motor. Also,
The CVT 103 is provided with a hydraulic pressure sensor 125 for detecting a hydraulic pressure Pl in the hydraulic pressure control circuit and an oil temperature sensor 126 for detecting an oil temperature Tmp, and an input shaft speed for detecting a CVT input shaft speed Nin. A sensor 123 is provided.

[0028] The torque converter 104
Pump directly connected to the crankshaft 2 and CV
It has a turbine directly connected to the input shaft of T103, a stator provided between the pump and the turbine via oil, and a lockup mechanism using a clutch member.

The final gear and the differential gear 106 are provided with a vehicle speed sensor 124 for detecting an output shaft speed proportional to the vehicle speed.

The engine 102 and the CVT 103 are a powertrain control module (hereinafter referred to as a PC).
M) 111. PCM111 is a CPU,
The PCM 111 includes an engine speed Ne from a crank angle sensor 121, a throttle opening TVO from a throttle opening sensor 122, and a PCM 111.
Signals such as the oil pressure Pl from the oil pressure sensor 125, the oil temperature Tmp from the oil temperature sensor, the steering angle δ from the steering angle sensor 128, and the vehicle speed signal VSP from the vehicle speed sensor 124 are input. The PCM 111 controls the fuel supply amount and the ignition timing of the engine 102 and controls the speed ratio and the oil pressure of the CVT 103 based on these various signals. In addition, the vehicle position information, road shape information, and the like from the navigation device 112 are input to the PCM 111 as needed.

The road surface gradient estimating device 110 includes the PCM
The speed ratio Ip calculated by the CVT control unit in the PCM 111 based on the CVT input shaft rotation speed and the output shaft rotation speed is input in addition to the various signals input to the 111, and the road surface gradient estimating device 110 outputs The gradient of the road on which the vehicle is currently traveling is estimated based on the vehicle.

Hereinafter, the configuration of the road surface gradient estimating device 110 will be described in detail.

FIG. 2 is a block diagram showing the road surface gradient estimating device 110.
The vehicle includes an effective vehicle drive torque calculator 1, a running resistance torque calculator 5, a turning resistance torque calculator 6, an acceleration resistance torque calculator 7, a subtractor 8, and a gradient calculator 9.

First, the effective vehicle drive torque calculating section 1 will be described. The effective vehicle drive torque calculation unit 1 includes an ideal vehicle drive torque calculation unit 2, a drive system loss torque calculation unit 3,
And a subtraction unit 4. The ideal vehicle drive torque calculation unit 2 calculates the engine speed N from the crank angle sensor 121.
e, the throttle opening TVO from the throttle opening sensor 122, the CVT input shaft rotation speed Nin from the input shaft rotation speed sensor 123, and the gear ratio I calculated by the PCM 11.
The ideal vehicle driving torque Tor is calculated based on p. FIG. 3 is a block diagram showing the ideal vehicle drive torque calculating unit 2, which will be described later in detail.

The drive system loss torque calculator 3 calculates the drive system loss torque Tlos based on the CVT input shaft rotation speed Nin, the speed ratio Ip, the oil pressure Pl of the oil pressure sensor 125, and the oil temperature Tmp from the oil temperature sensor 126. calculate.

The subtraction unit 4 calculates the effective vehicle drive torque Toy by subtracting the drive system loss torque Tlos from the ideal vehicle drive torque Tor.

FIG. 4 is a block diagram showing the drive system loss torque calculating section 3. The drive system loss torque calculation unit 3 refers to the map 35 based on the hydraulic pressure Pl and calculates the hydraulic contribution loss torque Tlpl with reference to the map 36 based on the input shaft speed Nin and the input rotation contribution loss Tlnin.
The transmission ratio contribution loss torque Tlip is calculated from the transmission ratio Ip with reference to the map 37, and the oil temperature contribution loss torque Tltmp is calculated from the oil temperature Tmp with reference to the map 38. The sum is output as the drive system loss torque Tlos.

Here, the hydraulic pressure Pl and the input shaft speed N
Although the drive system loss torque Tlos is calculated based on the four input signals of in, the gear ratio Ip, and the oil temperature Tmp, the drive system loss torque Tlos may be calculated from fewer input signals. For example, as shown in FIG. 5, if the drive system loss torque Tlos is calculated with reference to a map 39 represented by a quadratic curve from the oil pressure Pl, the control program is simplified, the execution speed is increased, and the program speed is increased. The capacity can be reduced.

Next, the running resistance torque calculator 5 will be described. The running resistance torque calculation unit 5 includes a vehicle speed sensor 124
Road running resistance torque Trl based on vehicle speed VSP from
Is calculated. FIG. 6 shows a block diagram of the running resistance torque calculation unit 5. The running resistance torque calculation unit 5 calculates the flat road running resistance torque Trl from the vehicle speed VSP with reference to the flat road running resistance torque map 51.

Next, the turning resistance torque calculator 6 will be described. The turning resistance torque calculation unit 6 includes a vehicle speed sensor 124
VSP from the steering angle and the steering angle δ from the steering angle sensor 128
The turning resistance torque Tcorn is calculated based on

FIG. 7 is a block diagram showing the turning resistance torque calculating section 6. The turning resistance torque calculation unit 6 calculates a Tcorn for turning resistance corresponding to the vehicle speed VSP and the steering angle δ with reference to the map 61. Here, the map 61 is a map having a threshold value for the vehicle speed VSP.
When the vehicle speed VSP is equal to or less than the threshold value A or the threshold value B, the turning resistance torque is not output.

By providing a threshold value for the vehicle speed VSP in this way, in a situation such as when the vehicle is running at a low speed and the turning resistance torque hardly affects the estimation of the road surface gradient, the process of calculating the turning resistance torque is omitted. The load on the calculation can be reduced. Note that here, the vehicle speed VS
Although a threshold value is provided for P, a threshold value may be provided for the steering angle δ. For example, when the steering angle δ is a certain value or less, the turning resistance torque may not be output.

The radius of curvature of the road on which the host vehicle is currently traveling is detected from the host vehicle position information obtained from the navigation device 112 and the road shape information recorded in the map database thereof. Curvature radius and vehicle speed V
The turning resistance torque Tcorn may be calculated based on the SP.

Next, the acceleration resistance torque calculator 7 will be described. The acceleration resistance torque calculation unit 7 includes a vehicle speed sensor 124
The acceleration resistance torque Tra is calculated based on the vehicle speed VSP from the vehicle. FIG. 8 is a block diagram showing the acceleration resistance torque calculation unit 6. The acceleration resistance torque calculator 7 calculates the vehicle speed V
SP is differentiated by the time differentiation operation unit 71 to calculate the acceleration Acel
Is calculated, and the acceleration Atra is calculated by multiplying the acceleration Acel by the vehicle weight Iv and the driving wheel radius r in the multipliers 73 and 75, respectively. That is, the acceleration resistance torque is represented by Tra = (dVSP / dt) · Iv · r (1)

The subtraction unit 8 subtracts the flat road running resistance torque Trl, the acceleration resistance torque Tra, and the turning resistance torque Tcorn from the effective vehicle driving torque Tor to obtain a gradient resistance torque T.
Calculate rg.

Then, the gradient calculator 9 calculates the gradient torque Trg.
From the road surface sin θ. Assuming that the vehicle weight is Iv and the drive wheel radius is r, the road surface gradient sin θ is represented by sin θ = Trg / (Iv · r) (2)

Next, the above-described ideal vehicle drive torque calculating section 2 will be described in detail with reference to a block diagram shown in FIG.

As shown in FIG. 3, the ideal vehicle driving torque calculating section 2 includes an engine output torque calculating section 21, an engine inertia torque calculating section 22, and a torque ratio calculating section 24.
, A subtraction unit 23, and multiplication units 25, 26, and 31.

The engine output torque calculating section 21 searches the engine torque map 33,
Engine speed Ne from the throttle opening sensor 12
Then, an engine output torque Te corresponding to the throttle opening TVO from Step 2 is obtained.

The engine inertia torque calculation unit 22 calculates
The engine speed Ne from the crank angle sensor 121 is time-differentiated by the time differentiation calculation unit 27 to calculate an engine speed differential value dNe / dt. Then, the engine inertia torque Tei is calculated by multiplying the engine speed differential value dNe / dt by the engine inertia constant Ieng in the multiplier 22a. That is, the engine inertia torque Tei is represented by Tei = (dNe / dt) · Ieng (3).

The torque ratio calculator 24 calculates the CVT input shaft rotation speed Nin from the input shaft rotation sensor 123 in the divider 29.
Is divided by the engine speed Ne from the crank angle sensor 121 to calculate the rotation speed ratio e of the torque converter 104. Then, a torque ratio τ corresponding to the rotation speed ratio e is obtained by searching a torque converter torque ratio map.

The subtraction unit 23 subtracts the engine inertia torque Tei calculated by the engine inertia torque calculation unit 22 from the engine output torque Te calculated by the engine output torque calculation unit 21 to obtain the actual engine output torque Te.
2 is calculated. Then, the multiplication unit 25 calculates the input torque Tin to the CVT 103 by multiplying the actual engine output torque Te2 by the torque ratio τ calculated by the torque ratio calculation unit 24.

Further, the multiplication unit 26 calculates the output torque Tsec from the CVT 103 by multiplying the input torque Tin by the speed ratio Ip from the PCM 111, and the multiplication unit 31 multiplies the output torque Tsec by the final gear ratio Final to obtain an ideal vehicle. The driving torque Tor is calculated. That is, the ideal vehicle driving torque Tor is represented by Tor = (Te−Tei) · τ · Ip · Final (4).

Next, the operation of the road surface gradient estimating device 110 will be described with reference to the flowchart shown in FIG.

First, in steps S11 to S17, an ideal vehicle driving torque Tor is calculated.

In step S11, the crank angle sensor 1
21, the engine speed Ne from the throttle opening sensor 122, the throttle opening TVO from the throttle opening sensor 122, the CVT input shaft rotation speed Nin from the input shaft rotation sensor 123, and PC
The gear ratio Ip from M111 is read.

In step S12, the engine torque map 33 is searched to find the engine output torque Te corresponding to the engine speed Ne and the throttle opening TVO. In step S13, the engine speed Ne is differentiated with respect to time to obtain the engine output torque Te. The rotational speed differential value dNe / dt is calculated, and the resultant value is multiplied by the engine inertia Ieng to calculate the engine inertia torque Tei.

In step S14, the rotation speed ratio e of the torque converter 104 is calculated by dividing the CVT input shaft rotation speed Nin by the engine rotation speed Ne. In step S15,
The torque ratio τ corresponding to the rotation speed ratio e is obtained by searching the torque converter torque ratio map 34.

Then, in step S16, step S
The input torque Tin of the drive system is calculated by multiplying the value obtained by subtracting the Tei calculated in step S13 from the engine output torque obtained in step 12 with the torque ratio τ obtained in step S14. In step S17, the ideal vehicle driving torque Tor is calculated by multiplying the input torque Tin by the speed ratio Ip and the final reduction ratio Final.

After calculating the ideal vehicle driving torque Tor,
Next, the effective vehicle drive torque Toy is calculated in steps S18 to S20.

First, in step S18, the hydraulic pressure sensor 1
25, and the oil temperature Tm from the oil temperature sensor 126.
p, and at step S19, the hydraulic pressure Pl and the oil temperature T
The drive system loss torque Tlos is obtained by referring to a predetermined loss torque map from at least one of the input signals mp, CVT input shaft rotation speed Nin, and gear ratio Ip.

Then, in step S20, step S1
The effective vehicle drive torque Toy is calculated by subtracting the drive system loss torque from the ideal vehicle drive torque Tor obtained in step 7.

After calculating the effective vehicle driving torque Toy,
Next, in steps S21 to S27, the flat road running resistance torque trl, the turning resistance torque Tcorn, and the acceleration resistance torque Tra are obtained, and the road surface gradient is estimated based on these.

First, in step S21, the vehicle speed sensor 1
24, and the steering angle δ from the steering angle sensor 128. Then, in step S22, the flat road running resistance torque Trl corresponding to the vehicle speed VSP is obtained with reference to the flat road running resistance torque map 51, and in step S23.
With reference to the turning resistance torque map 61, the turning resistance torque Tcorn corresponding to the vehicle speed VSP and the steering angle δ is obtained.

In step S24, the acceleration Acel is calculated by time-differentiating the vehicle speed VSP. In step S25, the acceleration Acel is calculated by multiplying the acceleration Acel by the vehicle weight Iv and the driving wheel radius r.

In step S25, the gradient resistance torque Trg is calculated by subtracting the flat road running resistance torque Trl, the turning resistance torque Tcorn, and the acceleration resistance torque Tra from the effective vehicle driving torque Toy. Then, in step S26, the gradient sin θ is calculated by dividing the calculated gradient resistance torque Trg by the vehicle weight Iv and the drive wheel radius r.

As described above, according to the present invention, the vehicle driving torque is calculated in consideration of the torque loss in the driving system, and the gradient resistance torque is calculated from the vehicle driving torque in consideration of the turning resistance torque.

As a result, the gradient resistance torque can be calculated more accurately than in the prior art in which the gradient resistance torque is calculated without considering the drive system loss torque and the turning resistance torque, and the road surface gradient can be calculated with higher precision. Can be estimated. Further, by considering the turning resistance torque, it becomes possible to estimate the road surface gradient at the time of turning, which was difficult in the past.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to the above embodiments. For example, in the above embodiment, the engine output torque Te is obtained by searching the engine torque map 33 from the engine speed Ne and the throttle opening TVO, but the engine output torque with respect to the fuel injection amount TP of the engine 102 and the engine speed Ne is obtained. A map defining the relationship between Te and the fuel injection amount TP and the engine speed Ne is prepared in advance.
The engine output torque may be obtained by searching the map for the engine output torque.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a vehicle provided with a road surface gradient estimating device according to the present invention.

FIG. 2 is a block diagram of a road surface gradient estimating device.

FIG. 3 is a block diagram of an ideal vehicle drive torque calculation unit.

FIG. 4 is a block diagram of a drive system loss torque calculation unit.

FIG. 5 is another example of a block diagram of a drive system loss torque calculation unit.

FIG. 6 is a block diagram of a running resistance torque calculation unit.

FIG. 7 is a block diagram of a turning resistance torque calculation unit.

FIG. 8 is a block diagram of an acceleration resistance torque calculation unit.

FIG. 9 is a flowchart illustrating the operation of the road surface gradient estimating apparatus.

[Explanation of symbols]

 Reference Signs List 101 vehicle 102 engine 103 CVT 104 torque converter 110 road surface gradient estimating device 111 PCM

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masaaki Uchida 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa F-term in Nissan Motor Co., Ltd. (reference) 3G084 BA13 BA17 BA32 DA04 DA13 EB08 FA00 FA04 FA05 FA06 FA10 FA20 FA32 FA33

Claims (7)

[Claims] A means for calculating an ideal vehicle drive torque by multiplying a drive system input torque by a drive system speed ratio; and at least one of a transmission hydraulic pressure, an oil temperature, an input shaft speed, and a speed ratio. Means for calculating a drive system loss torque based on: a means for calculating an effective vehicle drive torque by subtracting the drive system loss torque from the ideal vehicle drive torque; means for calculating a flat road running resistance torque based on the vehicle speed; Means for calculating an acceleration resistance torque based on the acceleration; means for calculating a slope resistance torque by subtracting the flat road running resistance torque and the acceleration resistance torque from the effective vehicle driving torque; and calculating a road surface gradient during running from the slope resistance torque. Means for estimating the road surface gradient. 2. An engine output torque calculating means, an engine inertia torque calculating means, a torque converter torque ratio calculating means, and a transmission gear ratio calculating means, The means for calculating the ideal vehicle drive torque calculates the drive system input torque based on the engine output torque, the engine inertia torque, and the torque ratio, and calculates the ideal vehicle drive torque by multiplying the drive system input torque by the speed ratio. The road surface gradient estimating device according to claim 1. 3. The road surface gradient according to claim 2, wherein the means for calculating the inertia torque of the engine calculates the engine inertia torque by multiplying a value obtained by differentiating the engine speed over time by the engine inertia. Estimation device. 4. The acceleration resistance torque calculating means calculates the acceleration resistance by calculating the acceleration of the vehicle by time-differentiating the vehicle speed, and multiplying the acceleration by the weight of the vehicle and the radius of the driving wheel. The road surface gradient estimating device according to any one of claims 1 to 3. 5. A vehicle comprising: means for detecting a steering angle of a vehicle; and means for calculating turning resistance torque based on the detected steering angle. The road surface gradient estimating device according to any one of claims 1 to 4, wherein the traveling resistance torque, the acceleration resistance torque, and the turning resistance torque are subtracted to calculate the gradient resistance torque. 6. A road surface gradient estimating apparatus according to claim 5, wherein said means for calculating the turning resistance torque does not calculate the turning resistance torque when the steering angle or the vehicle speed is equal to or less than a threshold value. 7. Means for detecting the position of the vehicle, means for calculating the radius of curvature of the road at the position of the vehicle based on map information, and means for calculating turning resistance torque based on the calculated radius of curvature, 5. The slope resistance torque is calculated by subtracting a flat road running resistance torque, an acceleration resistance torque and a turning resistance torque from the effective vehicle driving torque. 5. The road surface gradient estimating device according to one of the above aspects.